CN102439365A

CN102439365A - A preheater for combustion air, and a power plant

Info

Publication number: CN102439365A
Application number: CN2010800224229A
Authority: CN
Inventors: T.梅罗
Original assignee: Metso Power Oy
Current assignee: Valmet Power Oy
Priority date: 2009-05-22
Filing date: 2010-05-21
Publication date: 2012-05-02
Also published as: CA2777496A1; RU2011152388A; CL2011002940A1; FI20095566A0; BRPI1010943A2; US20120060774A1; FI20095566A; EP2433055A1; WO2010133773A1

Abstract

A preheating device (1 ) for combustion air in a boiler, the device comprising first heat exchanger structures fitted in a flue gas duct (2), for heating primary air (P), a first air supply area (5) in the wall of the flue gas duct (2), for supplying air to be heated to the first heat exchanger structures, second heat exchanger structures fitted in a flue gas duct (2), for heating secondary air (S), as well as a second air supply area (6) in the wall of the flue gas duct (2), for supplying air to be heated to the second heat exchanger structures. The first air supply area (5) is opposite the second air supply area (6). The invention also relates to a power plant.

Description

The preheater and the power plant that are used for combustion air

Technical field

The present invention relates to a kind ofly be used for boiler in the power plant with the equipment of flue gas with the combustion air preheating.In addition, the present invention relates to a kind of power plant, it comprises the equipment that makes the combustion air preheating that will be supplied in the boiler by means of flue gas.

Background technology

In order to be used for the combustion air preheating of solid fuel fired boiler; Usually use flue gas air preheater (LUVO); Wherein, heat medium (being flue gas) flows in the heat exchanger tube outside, and medium to be heated (being air) is in the heat exchanger tube internal flow.Heat exchanger tube flatly is placed in the fume pipe, and the heat exchanger unit on the different level is interconnected by the air hose in the fume pipe outside.Also have such structure, wherein flue gas flows and pipeline is vertical at pipe interior.

At typical combustion air pre-heating device 1 shown in Fig. 1.This pre-heating device 1 comprises and being placed in the fume pipe 2 so that with the horizontal heat exchanger structure 3 and the heat exchanger structure 4 that is used for auxiliary air S heating of primary air P heating.The independent

air supplies zone

5,6 that is used for two air circulation is provided, so that supply is with heated air in

heat exchanger structure

3,4 on the wall of fume pipe 2.In this structure, the connection of air hose is made into for the layout of factory favourable as far as possible.Primary air P and auxiliary air S are supplied to preheater 1 from the same side.This structure causes the strong distortion of the temperature of flue gas F, because all cold airs all are supplied to preheater 1 from a side, cause and compares at opposite side, and flue gas is in the obvious stronger cooling of air inlet side.Flue gas F is in the strong cooling of air inlet side and then cause the low relatively material temperature at inlet end place of pipeline of the

heat exchanger structure

3,4 of preheater 1, although flue gas has high relatively mean temperature.Therefore, easily realize the dew-point temperature of flue gas in the surface of heat exchanger structure 3,4.This dew point and then will cause deep-etching and the erosion in the cold

heat exchanger structure

3,4 at short notice is particularly under the situation of difficult fuel.

Summary of the invention

Now, had been found that a solution, it makes it possible in the terminal part of fume pipe, realize that more even temperature distributes.

In order to reach this purpose, mainly be the content that proposes in independent claims 1 according to the characteristic of combustion air pre-heating device of the present invention.And then, mainly be the content that proposes in independent claims 8 according to the characteristic in power plant of the present invention.Other dependent claims will propose preferred embodiments more of the present invention.

Basic thought of the present invention is through being provided for that for fume pipe first heat exchanger structure of primary air heating is formed a kind of pre-heating device that is used for the combustion air of boiler with second heat exchanger structure that is used for the auxiliary air heating.The import of the import of first heat exchanger structure and second heat exchanger structure is placed on the same horizontal plane basically, and this horizontal plane is substantially perpendicular to the center line of fume pipe.

In one embodiment, first heat exchanger structure and second heat exchanger structure interlock.

In one embodiment, first heat exchanger structure and second heat exchanger structure extend to the central area of fume pipe in its air supplies location, and it provides the air flow deflector structure of the airflow direction that is used to change heat exchanger.Deflection structure can be for example chamber or bend pipe.

In one embodiment, form first heat exchanger structure and second heat exchanger structure through bending, make the center line of straight part and fume pipe of pipeline vertically extend abreast and with the center line of fume pipe by pipeline.

A kind of power plant according to basic thought of the present invention comprises boiler and fume pipe at least, and the gas that leaves boiler is introduced in the fume pipe.In addition, this factory comprises the above-mentioned pre-heating device that is used for making the combustion air heating that will be supplied to boiler.In advantageous embodiment, fume pipe is vertical, and is introduced and discharge from the bottom from the top of fume pipe from the flue gas of boiler.

In one embodiment, first air supplies zone and the second air supplies zone are placed on the sustained height place basically.

In one embodiment, first air supplies zone and the second air supplies zone are the lowermost portion that is placed on the preheater in the fume pipe.

Individually and the different embodiment of the above-mentioned structure that obtains with different combinations various advantages are provided.Single embodiment can comprise one or more in the following advantage according to its embodiment:

-the distortion that can remove smoke;

Even-in the front and rear of the pre-heating device minimum row's among both pipeline, also can make the temperature difference between flue gas and the combustion air big as far as possible;

-can improve the material temperature of the pipeline of pre-heating device in the position of inlet air flow;

The pipe arrangement of-factory is than simpler in conventional configurations;

-in the zone of bend pipe element, possibly reduce the vibration problem of pre-heating device, because in one embodiment, vertically in the part pipeline is being tied;

-in one embodiment, reduced the vibration problem of pre-heating device, because harness (bundle) comprises the primary air pipeline and the auxiliary air pipeline of mutual vicinity; Maybe be by once having different frequencies with the vibration that the hair-dryer of auxiliary air side causes, wherein, they do not amplify each other.

The advantage that advantageous embodiment has is that the cold harness of primary air and auxiliary air is set to single minimum harness.Therefore, when needs are replaced the harness that damages, only must replace single harness.Usually, when etching problem for example takes place when, usually need according to give the replacement of working out a scheme minimum once with the auxiliary air harness.It is especially difficult replacing low harness second from the bottom.

In application according to an embodiment of the invention, the flow velocity once advantageously increased the flue gas of locating in the end of flowing gas pipeline with the supercentral air deflection chamber of auxiliary air harness has improved the heat transmission on fume side.Thereby this help to improve the pre-heating device in the cold part of most critical pipeline material temperature and reduce the risk of the corrosive pipeline that the influence by acid dew point causes.

In advantageous embodiment, the heat transfer surface of pre-heating device integrally is made up of the duct element that extends to the top from the bottom.For example be used for making this element on the crooked pipeline of superheater pipeline.About adjacent elements, one is to be used for primary air and another is to be used for auxiliary air.The size of pipeline can be to equate or different, depends on once the mutual ratio with auxiliary air.Spacing between pipes can be typical 75 * 75 mm, and perhaps can this spacing be chosen as provides the flue gas of expectation speed.Except the advantage that preceding text propose, said structure provides following advantage and other advantages than conventional configurations:

-interface channel between the harness of air side is all removed, and the significant cost savings of making the pipeline aspect are provided;

The space in the boiler room has been saved in the removal of-interface channel;

The installation of-pre-heating device becomes faster, because the connection air duct need be installed;

-pre-heating device is divided into installation unit by the width along pre-heating device;

-littler in conventional preheater equipment at the pressure loss ratio of air side, because eliminated the inflow and the effluent of the pipeline between the harness;

Single resistance coefficient in-90 ° of bendings is than lower in the inflow of pipeline or effluent.This has saved the internal consumption of boiler.

Description of drawings

Below, will come to describe in more detail the present invention with reference to appended schematic diagram, in the accompanying drawings

Fig. 1 is at the combustion air preheater of prior art shown in the schematic diagram;

Fig. 2 is in power plant shown in the schematic diagram;

Fig. 3 illustrates first embodiment of preheater;

Fig. 4 illustrates second embodiment of preheater,

Fig. 5 illustrates the 3rd embodiment of preheater;

Fig. 6 illustrates the 4th embodiment of preheater;

Fig. 7 illustrates the details of the preheater of Fig. 8;

Fig. 8 illustrates the 5th embodiment of preheater;

Fig. 9 illustrates the cross section of the line A-A in Fig. 8;

Figure 10 illustrates the details of the preheater of Fig. 9;

Figure 11 illustrates the details of the preheater of Figure 12;

Figure 12 illustrates the 6th embodiment of preheater;

Figure 13 illustrates the cross section of the line B-B in Figure 12;

Figure 14 illustrates the 7th embodiment of preheater;

Figure 15 illustrates the application of preheater.

For the purpose of clear, accompanying drawing only is to understand details required for the present invention.For understanding the present invention, do not need conspicuous for a person skilled in the art structure and details so that stress characteristic of the present invention but omitted in the drawings.

The specific embodiment

Fig. 2 is in the power plant that in fume pipe 2, has combustion air preheater 1 shown in the schematic diagram.In this example, the power plant comprises CFBB 7, but this boiler also can be another type.As can see in the drawings, fume pipe 2 is between boiler 7 and chimney 8.In addition, fume pipe can be included in not shown superheater and filter.

In the example of Fig. 2, the bottom of preheater 1 comprises

air inlet zone

5,6, and primary air P to be heated and auxiliary air S are supplied to the heat exchanger structure of preheater that is heat transfer surface through this air inlet regional 5,6.The

air supplies zone

5,6 of primary air P and auxiliary air S is placed on the opposite side of fume pipe 2, basically on same horizontal plane.

Along the flow direction of flue gas F, the heat exchanger structure that in

air supplies zone

5,6, stops is last some that are placed in the heat exchanger structure of the preheater 1 in the fume pipe 2.In example, fume pipe 2 is vertical, and flue gas F flows downward from upper horizontal plane, makes

air supplies zone

5,6 be placed on lowest part.During beginning (that is, in this example, on upper horizontal plane); Flue gas F is than in the end (in this example; On the bottom) in hotter, thereby when combustion air P, S were heated before the outlet at the place, top of preheater 1 at last, can make combustion air P, S hotter.

The basic thought of this structure is that

air supplies zone

5,6 is vertically faced on the relative wall of fume pipe 2 each other.In horizontal fume pipe 2, this means

air supplies zone

5,6 against each other, basically at the sustained height place.If fume pipe 2 is on another position, then

air supplies zone

5,6 is in same district, and this district is perpendicular to the center line 2X of fume pipe 2.

To guide to the boiler 7 from the top of preheater with the primary air P of preheater 1 heating and auxiliary air S with suitable channel design.In this example, primary air P is supplied to the import of fluidization air, and auxiliary air S is supplied to the air supplies horizontal plane on the wall of boiler 7.In preheater 1, combustion air P, S are heated to about 150 to 250 ℃ temperature.

The heat exchanger of preheater 1 is made up of one or more unit.In this article, the unit refers to condensate, and wherein, the end of pipeline extends to another wall of fume pipe from a wall of fume pipe 2.Preferably, the unit in the vertical fume pipe 2 comprises 20 to 30 pipelines of mutual superposition and about 100 pipelines of mutual vicinity.

In addition, a unit can be by being formed by interconnective one or more subelements.Preferably, the unit is made up of two or more sub-cells.The structure of the preheater that is assembled by a plurality of subelements is usually easier than the structure of the preheater of single big unit.

Fig. 3,4,5,8 and 12 shows some application, and wherein, the preheater 1 that is used for combustion air is composed of multiple units.Mainly the pipeline of heat transmission effective heat exchange device structure is laterally placed with respect to the flow direction of the flue gas F in the fume pipe 2.In Fig. 3, the structure shown in 4 and 5, lowest element 9 be used for once with auxiliary air P, S the two.Lowest element 9 is called as cold unit, the air that will use preheater 1 to heat to lowest element 9 supplies from air supplies zone 5,6.In according to Fig. 3,4 and 5 structure, the highest unit 10 has structure like the unit class with conventional preheater; That is to say that primary air P or auxiliary air S are supplied to individual unit individually.

The pipeline of same air circulation can be close to each other, and wherein, the structure of this structure and Fig. 3 is similar.In the structure of Fig. 3, the pipeline of the pipeline of primary air cycle P and auxiliary air circulation S is at the opposite side of fume pipe 2.This structure can also be implemented as and make and whenever to be used for primary air P and whenever to be used for auxiliary air S at a distance from one at a distance from a duct element, and wherein, this structure is similar to the structure of Fig. 4.

In the application according to the embodiment of the invention shown in Figure 5, provide air deflection chamber 11 as be used for lowest element 9 once with the deflection structure of the supercentral air-flow of auxiliary air structure.Air deflection chamber 11 comprises and being used for once and both independent mechanisms of auxiliary air circulation.Preferably, air deflection chamber 11 reduces the area of section of fume pipe 2 and is increased in the flow velocity of flue gas F of the terminal part office of fume pipe, improves the heat transmission of fume side.In addition, the embodiment of Fig. 5 is favourable for the replaceability of unit, because the cold heat exchanger structure of two air circulation is placed on the lowest part of the

unit

9,10 of preheater.In the structure of Fig. 5, lowest element 9 is made up of pipe section 12 and deflection chamber 11.The primary air cycle P comprises two sections 12, and it is made up of the pipeline and the space of the deflection chamber 11 that connects.In the corresponding way, auxiliary air circulation S is made up of two parts 12, and two parts 12 are made up of the pipeline and the space of the deflection chamber 11 that connects.As can see the

import

5,6 of the air circulation of lowest element 9 and export 13 on the different horizontal face in this example.On the flow direction of flue gas F, outlet 13 is in import 5, before 6.In this vertical fume pipe 2, wherein, flue gas F flows downward from upper horizontal plane, and outlet 13 is higher than import 5,6.

A Fig. 6 and then application is shown, wherein preheater 1 is made up of individual unit 14.In the present embodiment, use heat exchanger structure from cold junction to the continuous conduit of hot junction extension that realize preheater 1 from.In this advantageous embodiment, the heat transfer surface of pre-heating device 1 integrally is made up of the duct element that extends to the top from the bottom.And in this structure, mainly the pipeline of heat transmission effective heat exchange device structure is laterally placed with respect to the flow direction of the flue gas F in the fume pipe 2.In advantageous embodiment, in the adjacent elements one is used for primary air and another is used for auxiliary air.The size of pipeline can be equal or different, depends on the mutual ratio of primary air P and auxiliary air S.Can be as required with the diameter of pipeline be chosen as for once with auxiliary air side P, S for be different.Spacing between pipes can be for example normal 75 * 75 mm, and perhaps this spacing can be selected as provides the flue gas of expectation speed.In one embodiment, make once and interlock, thereby in recurrent series, have two pipelines of primary air circulation and two pipelines that contiguous with it auxiliary air circulates with auxiliary air cycle P, S.In another embodiment, and then, in recurrent series, exist once or two pipelines of auxiliary air circulation, and a pipeline of secondary or primary air circulation is between it.

Fig. 7 to 10 shows an embodiment, wherein realizes the top 15 of the heat exchanger structure of preheater with continuous conduit.And then, in the cold junction of heat exchanger structure, use air deflection chamber 11 as the deflection structure that is used for once with the supercentral air-flow of auxiliary air unit.Fig. 7 illustrates the part of the details among Fig. 8 and amplifies, and how the pipeline that the unit is shown has two 90 ° deflection.

Fig. 9 illustrates the cross section of the position A-A among Fig. 8.Figure 10 illustrates the part of the details among Fig. 9 and amplifies.Can see from Fig. 9 and 10 how the pipeline of unit is placed on the different level t1-t6 of preheater 1.In the example of Figure 10, the pipeline crested of primary air cycle P, and the not crested of pipeline of auxiliary air circulation S.In this example, make with dashed lines indicate the corresponding relation of some last pipelines of different level t4, t5.

Figure 11 to 13 shows another embodiment, wherein realizes the top 16 of the heat exchanger structure of preheater 1 with continuous conduit.And in this example, in the cold junction of heat exchanger structure, use air deflection chamber 11 as the deflection structure that is used for once with the supercentral air-flow of auxiliary air unit.Figure 11 illustrates two outermost pipeline 16a on the top 16 of primary air cycle P.Can see in the drawings, process heat exchanger structure by pipeline through bending, thereby the center line 2X of the straight part quilt of pipeline and fume pipe 2 is placed vertically abreast and with the center line of fume pipe.

Preferably, for example the pipe section parallel with the center line 2X of fume pipe 2 interconnected through binding.Therefore, reduce possibly being shifted and vibrating of pipeline, thereby and also reduced the vibration problem of pre-heating device 1.

Figure 13 illustrates the cross section of the position B-B among Figure 12.How can to see in the drawings that the pipeline with the unit is placed on the different level t1-t6 of preheater.Essential difference between the example among Fig. 7 to 10 and shown in Figure 11 to 13 is the density that pipeline is connected to the top of deflection chamber.In the structure of Figure 11 to 13, the horizontal range between the adjacent channel is substantially equal to the horizontal range between the adjacent channel in the top of preheater.In other words, the horizontal range between the adjacent channel is identical on all horizontal plane t1 to t6 basically.

In the structure shown in Fig. 7 to 10, the horizontal range between the pipeline of the auxiliary air circulation S among the top t5 of deflection chamber 11 is substantially equal to the horizontal range between the pipeline of the auxiliary air circulation among the top t1-t4 of preheater 1.And the horizontal range between the pipeline of the primary air cycle P among the top t5 of deflection chamber 11 is substantially equal to the horizontal range between the pipeline of the primary air circulation among the top t1-t4 of preheater 1.In the t6 of the bottom of deflection chamber 11, the density of pipeline is with identical in the t1-t4 of the top of preheater 1.At the opposite side of deflection chamber 11, all pipelines of bottom t6 all are pipelines of primary air cycle P, and all are pipelines of auxiliary air circulation S at those of opposite side.

Figure 14 also illustrates an embodiment, wherein realizes the top 15 of the heat exchanger tube of preheater 1 with continuous conduit.In the present embodiment, feeding chamber 11' is used for once the supplying with the auxiliary air unit of cold junction 9 places of heat exchanging device structure.Feeding chamber 11' be placed on fume pipe 2 the bottom in the heart, there, from the outside of fume pipe, preferably introduce air to be heated from the end of feeding chamber 11'.Feeding chamber 11' comprises and is used to the primary air source of supply zone 5 and SAS Secondary Air Supply source region 6 that heat exchanger structure is supplied air to be heated.From feeding chamber 11' along different direction supply primary air P and auxiliary air S, and as can see in the drawings, the air supplier in first air supplies regional 5 to the air supplier of SAS Secondary Air Supply source region 6 to becoming 180 ° of angles.

In addition, for the cleaning and the maintenance of preheater 1, this equipment comprises other structure except that the said units of preheater.Accompanying drawing shows cigarette ash device (sooting means) 17, maintenance hatch 18 and ash disposal opening 19.In addition, this equipment can also comprise not shown other structure and part.

In above-mentioned example, fume pipe 2 is vertical, and flue gas F flows downward from upper horizontal plane, thereby air supplies

zone

5,6 is placed on lowest part.Can also realize fume pipe with other type.For example, in Figure 15, fume pipe 2 is vertical, makes flue gas F upwards flow from the bottom, and wherein, air supplies

zone

5,6 is placed on highest point.Fume pipe can also be a level for example fully or partly, and in this case, flue gas flows along horizontal direction.During beginning, flue gas is warmmer than locating in the end, and when being heated at last before the outlet of combustion air at the initial end place of fume pipe, can make combustion air hotter.

To combining disclosed pattern of above-mentioned different embodiment of the present invention and structure to make up, can produce various embodiment of the present invention through in every way according to spirit of the present invention.Therefore, example set forth above should not be interpreted as restriction the present invention, but freely changes in the scope of the creative feature that embodiments of the invention can propose in accompanying claims.

Claims

1. pre-heating device (1) that is used for the combustion air of boiler, said equipment comprises:

-be assemblied in first heat exchanger structure in the fume pipe (2), be used for primary air (P) heating, and

-be assemblied in second heat exchanger structure in the fume pipe (2), be used for auxiliary air (S) heating,

It is characterized in that the import of the import of said first heat exchanger structure and said second heat exchanger structure is placed on the same horizontal plane basically, said horizontal plane is substantially perpendicular to the center line of said fume pipe.

2. pre-heating device according to claim 1; It is characterized in that; Said first heat exchanger structure comprises the one group of heat exchanger tube that forms primary air circulation (P); The primary air flow therein, and said second heat exchanger structure comprises the one group of heat exchanger tube that forms auxiliary air circulation (S), auxiliary air flow therein.

3. pre-heating device according to claim 1 and 2 is characterized in that, said equipment also comprises:

The source of supply of-said first heat exchanger structure is used for to primary air circulation (P) supply primary air to be heated, and

The source of supply of-said second heat exchanger structure is used for to auxiliary air circulation (S) supply auxiliary air to be heated.

4. according to each the described pre-heating device in the claim 1 to 3; It is characterized in that; Said equipment is included in first air supplies zone (5) in the wall of said fume pipe (2); Be used for to said first heat exchanger structure supply air to be heated; And be included in second air supplies zone (6) in the wall of said fume pipe (2), be used for to said second heat exchanger structure supply air to be heated, and said first air supplies zone (5) is relative with said second air supplies zone (6).

5. pre-heating device according to claim 4; It is characterized in that; Said first heat exchanger structure and said second heat exchanger structure locate to extend to the central area of said fume pipe (2) in air supplies zone (5,6); It has the deflection structure (11) that is used for air-flow (P, S), so that change the airflow direction of heat exchanger.

6. according to each the described pre-heating device in the aforementioned claim 1 to 5, it is characterized in that said first heat exchanger structure and said second exchanger arrangement interlock.

7. according to each the described pre-heating device in the aforementioned claim 1 to 6; It is characterized in that; Form said first heat exchanger structure and said second exchanger arrangement by pipeline through bending, make the center line (2X) of straight part quilt and said fume pipe (2) of pipeline be placed vertically abreast and with the center line of said fume pipe.

8. a power plant comprises boiler (7) and fume pipe (2) at least, and the flue gas (F) that leaves boiler is drawn towards said fume pipe (2); Said power plant also comprises the pre-heating device (1) that is used for making combustion air (P, the S) heating that will be supplied to said boiler, and said pre-heating device comprises:

9. power plant according to claim 8; It is characterized in that; Said first heat exchanger structure comprises the one group of heat exchanger tube that forms primary air circulation (P); The primary air flow therein, and said second heat exchanger structure comprises the one group of heat exchanger tube that forms auxiliary air circulation (S), auxiliary air flow therein.

10. according to Claim 8 or 9 described power plants, it is characterized in that said pre-heating device also comprises:

11. each described power plant in 10 according to Claim 8; It is characterized in that; The pre-heating device in said power plant is included in first air supplies zone (5) in the wall of said fume pipe (2); Be used for to said first heat exchanger structure supply air to be heated; And be included in second air supplies zone (6) in the wall of said fume pipe (2), be used for to said second heat exchanger structure supply air to be heated, and said first air supplies zone (5) is relative with said second air supplies zone (6).

12. power plant according to claim 11 is characterized in that, said first air supplies zone (5) and said second air supplies zone (6) are located substantially on the equal height place.

13., it is characterized in that said first air supplies zone (5) and said second air supplies zone (6) are the lowermost portion that is placed on the said preheater (1) in the said fume pipe (2) according to claim 11 or 12 described power plants.

14., it is characterized in that said first air supplies zone (5) and said second air supplies zone (6) are the highest parts that is placed on the said preheater (1) in the said fume pipe (2) according to claim 11 or 12 described power plants.

15. each described power plant in 13 according to Claim 8; It is characterized in that; Said fume pipe (2) is vertical, and is introduced the said fume pipe and from the bottom from the top of said fume pipe from the flue gas (F) of said boiler (7) and to remove.

16. each described power plant in 12 or 14 according to Claim 8; It is characterized in that; Said fume pipe (2) is vertical, and is introduced the said fume pipe and from top from the bottom of said fume pipe from the flue gas (F) of said boiler (7) and to remove.